Symplocarpus is one of the earliest plants to flower in spring in northeastern North America, sometimes with spathes emerging through snow on the ground. Because inflorescences are developed during the previous summer, flowering can occur during any warmer than normal weather throughout winter. The spadices of both Asian and American plants produce heat during flowering and can reach temperatures up to 25°C above ambient air temperature (R. M. Knutson 1972; S. Uemura et al. 1993). These elevated temperatures probably play a role in pollination and in facilitating floral development at cold temperatures.